In order to increase a capacity of a memory and reduce a bit cost, miniaturization, high integration, and the like of a semiconductor device have been performed so far. However, it is expected that a miniaturization process technology will be even more difficult, costs of a processing device will be steeply risen, and difficulty of the device will be increased. Therefore, reduction in the bit cost brought about by miniaturization becomes extremely difficult.
In recent years, as a method of reducing the bit cost while maintaining a large capacity without depending entirely on miniaturization, a 3D structure device, which is obtained by three-dimensionally forming a conventional planar structure, has been developed. The 3D structure device is a stacked LSI and therefore has a thicker layer than that of a conventional device. Therefore, in a step for forming a hole, a trench, or the like, an aspect ratio thereof (a ratio of a plane size of the hole or the trench to a depth thereof) tends to be further increased. Thus, an inspection technology and a measurement technology for evaluating performance of a sample in such development of the 3D structure device become more important.
A conventional inspection technology and a conventional measurement technology mainly use a low acceleration voltage region in view of resolution and secondary electron generation efficiency. However, because the aspect ratio becomes larger than before in the 3D structure device, it becomes difficult to observe a bottom of a hole, a trench, or the like with the conventional inspection method and the conventional measurement method.
As a method of compensating this, there is a method of irradiating a deeper position of a sample with electrons in a condition of a high acceleration voltage. With this method, secondary electrons and reflection electrons are efficiently detected, which makes it possible to observe a hole, a trench, or the like and perform inspection and measurement. PTL 1 discloses a semiconductor device analysis device capable of accurately analyzing a microstructure in a bottom of a hole having a large aspect ratio by using a substrate current.